WO2024019593A1 - Procédé de fabrication d'un matelas d'aérogel de silice hydrophobe et matelas d'aérogel de silice - Google Patents

Procédé de fabrication d'un matelas d'aérogel de silice hydrophobe et matelas d'aérogel de silice Download PDF

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WO2024019593A1
WO2024019593A1 PCT/KR2023/010608 KR2023010608W WO2024019593A1 WO 2024019593 A1 WO2024019593 A1 WO 2024019593A1 KR 2023010608 W KR2023010608 W KR 2023010608W WO 2024019593 A1 WO2024019593 A1 WO 2024019593A1
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Prior art keywords
wet gel
blanket
acid
aqueous solution
silica airgel
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PCT/KR2023/010608
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English (en)
Korean (ko)
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이규련
김미리
오명은
오경실
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주식회사 엘지화학
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Publication of WO2024019593A1 publication Critical patent/WO2024019593A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/113—Silicon oxides; Hydrates thereof
    • C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
    • C01B33/14—Colloidal silica, e.g. dispersions, gels, sols
    • C01B33/157—After-treatment of gels
    • C01B33/158—Purification; Drying; Dehydrating
    • C01B33/1585—Dehydration into aerogels
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/113—Silicon oxides; Hydrates thereof
    • C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
    • C01B33/14—Colloidal silica, e.g. dispersions, gels, sols
    • C01B33/157—After-treatment of gels
    • C01B33/158—Purification; Drying; Dehydrating
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/113—Silicon oxides; Hydrates thereof
    • C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
    • C01B33/14—Colloidal silica, e.g. dispersions, gels, sols
    • C01B33/157—After-treatment of gels
    • C01B33/159—Coating or hydrophobisation
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/32—Thermal properties
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/80—Compositional purity

Definitions

  • the present invention relates to a method for producing a silica airgel blanket with excellent surface modification efficiency and high hydrophobicity that does not contain residual chlorine, and to a silica airgel blanket that does not contain residual chlorine produced thereby.
  • Aerogel is an ultraporous, high-specific surface area ( ⁇ 500 m 2 /g) material with a porosity of about 90 to 99.9% and a pore size in the 1 to 100 nm range, and has excellent properties such as ultra-light weight, ultra-insulation, and ultra-low dielectric properties. Since it is a material that has airgel material development research, as well as application research for transparent insulation and environmentally friendly high-temperature insulation, ultra-low dielectric thin films for highly integrated devices, catalysts and catalyst carriers, electrodes for super capacitors, and electrode materials for seawater desalination, are also actively being conducted. .
  • airgel has super-insulation property, which shows a thermal conductivity of less than 0.300 W/m ⁇ K, which is lower than conventional organic insulation materials such as Styrofoam.
  • it can solve the fatal weaknesses of organic insulation materials such as fire vulnerability and harmful gas generation during fire.
  • airgel has a complex manufacturing process and high manufacturing cost, so despite having such excellent material properties, it is used only for extremely limited purposes.
  • the mechanical strength is very weak, so it has the disadvantage of being easily broken by even a small impact. Therefore, recently, airgel blanket composite technology has been studied to compensate for the shortcomings of airgel itself and enable processing into various forms.
  • An airgel blanket refers to a product made by combining airgel materials into a mattress or sheet form, and is flexible and can be bent, folded, or cut. Accordingly, it can be applied to pipe insulation, clothing, etc., and various industrial applications are also possible. Flexibility is possible because the airgel blanket is a composite composed of fiber and airgel. Fibers play a role in strengthening the flexibility and mechanical strength of the airgel blanket, and airgel provides insulation properties due to its porosity.
  • the core composite technology of airgel blankets is to combine the characteristics of fiber and airgel to take advantage of each other's strengths and complement their weaknesses.
  • Airgel blankets are a new material with better heat resistance and insulation than existing polymer insulators such as polystyrofoam or polyurethane foam, and are attracting attention as a cutting-edge material that can solve future energy saving and environmental problems.
  • Silica airgel blankets are manufactured by mixing fibers with silica sol obtained from water glass or alkoxide-based precursors, gelling them, then maturing, surface modifying, and drying, and the surface modification is performed by impregnating the fibers with silica sol and then adding acid together with a hydrophobizing agent. It is carried out by adding a catalyst.
  • the hydrophobizing agent is immiscible with water and has no reactivity with wet gels, especially hydrogels made by gelling water glass, so a method of solvent replacement with an amphiphilic organic solvent such as ethanol is used, or trimethylchlorosilane (TMCS) is used.
  • Patent Document 1 US 5,789,075 B
  • the problem to be solved by the present invention is to provide a silica airgel blanket that has excellent surface modification efficiency and does not contain residual chlorine, thereby eliminating corrosion problems that may arise when applying the silica airgel blanket, thereby demonstrating excellent stability. It provides a manufacturing method.
  • Another problem to be solved by the present invention is to provide a silica airgel blanket that does not contain chlorine.
  • the present invention provides a method for manufacturing a silica airgel blanket and a silica airgel blanket.
  • the present invention includes the steps of 1) preparing silica sol containing a water glass solution; 2) impregnating the blanket substrate with the silica sol; 3) preparing a wet gel by gelling the silica sol while impregnating the blanket substrate with the silica sol; 4) immersing the wet gel in an aqueous acid mixture solution containing aqueous acetic acid and nitric acid and surface modifying the wet gel with an alkyldisiloxane-based compound; and 5) drying the surface-modified wet gel, wherein the acetic acid concentration (w/w) after step 4) is 30% to 90%, and the nitric acid concentration (w/w) is 5% to 10%.
  • a method for manufacturing a silica airgel blanket is provided.
  • the present invention provides a method for producing a silica airgel blanket according to [1] above, wherein the acetic acid concentration (w/w) is 35% to 80%.
  • the present invention provides a method for producing a silica airgel blanket according to [1] or [2], wherein the nitric acid concentration (w/w) is 5% to 10%.
  • the present invention involves immersing the wet gel in an aqueous acid mixture solution in step 4), followed by surface modification with the alkyldisiloxane-based compound.
  • a method for manufacturing a silica airgel blanket in which the processes are performed sequentially is provided.
  • step 4 in any one of the above [1] to [4], in step 4), the acid mixture aqueous solution and the alkyldisiloxane-based compound are sequentially added to the wet gel, or the acid mixture
  • a method for producing a silica airgel blanket is provided in which an aqueous solution and the alkyldisiloxane-based compound are simultaneously added to the wet gel.
  • step 4 the alkyldisiloxane-based compound is added in a volume ratio of 1 to 3 times based on the volume of the wet gel. , provides a method for manufacturing a silica airgel blanket.
  • the present invention provides a method for producing a silica airgel blanket according to any one of [1] to [6] above, wherein the alkyldisiloxane-based compound is hexa(C 1-8 alkyl)disiloxane.
  • the present invention provides a method for producing a silica airgel blanket according to any one of [1] to [7] above, wherein the method for producing a silica airgel blanket is performed under chlorine-free (Cl-free) conditions.
  • the present invention provides a silica airgel blanket having a thermal conductivity of 12 mW/mK to 19 mW/mK and a Cl content of 0 ppm to 500 ppm.
  • the present invention provides a silica airgel blanket according to [9] above, wherein the silica airgel blanket has a Cl content of 0 ppm to 200 ppm.
  • the method for producing hydrophobic silica airgel according to the present invention has excellent surface modification efficiency and can produce a silica airgel blanket with high hydrophobicity that does not contain residual chlorine, so it is used in industries that require it, especially silica with high hydrophobicity. It can be usefully applied to industries that require airgel or industries that require silica airgel with the above-mentioned range of hydrophobization degrees.
  • silica wet gel manufactured using water glass has pores filled with water as a solvent.
  • the solvent When the solvent is simply dried and removed, the liquid solvent evaporates into the gas phase and forms a pore at the gas/liquid interface. Due to the high surface tension of water, shrinkage and cracking of the pore structure are likely to occur, resulting in a decrease in surface area and changes in the pore structure. Therefore, in order to maintain the pore structure of the wet gel, it is not only necessary to replace water with a high surface tension with an organic solvent with a relatively low surface tension, but also to maintain the structure of the wet gel without shrinkage. Skills for cleaning and drying are required.
  • dried silica airgel maintains low thermal conductivity immediately after drying, but has the disadvantage of absorbing water in the air due to the hydrophilic nature of the silanol group (Si-OH) on the silica surface, causing the thermal conductivity to gradually increase.
  • silica in order to reduce the shrinkage and occurrence of cracks in the pore structure due to the high surface tension of water at the gas/liquid interface when drying the silica wet gel, and to maintain low thermal conductivity by reducing the water absorption rate of the dried silica airgel, silica There is a need to modify the airgel surface to make it hydrophobic. Accordingly, a method of modifying the surface of silica airgel to make it hydrophobic using a surface modifier is widely used.
  • TMCS trimethylchlorosilane
  • HMDS hexamethyldisilazane
  • DMDES dimethyldiethoxysiloxane
  • HMDSO hexamethyldisiloxane
  • TMES trimethylethoxysilane
  • At least one surface modifier selected from the group consisting of is used.
  • HMDS hexamethyldisilazane
  • DMDES dimethyldiethoxysiloxane
  • HMDSO hexamethyldisiloxane
  • TMES trimethylethoxysilane
  • trimethylchlorosilane TMCS
  • HMDSO hexamethyldisiloxane
  • trimethylchlorosilane produces HCl after a surface modification reaction as shown in Scheme 1 below, so the final There is a problem that some chlorine remains in the silica airgel blanket obtained by causing corrosion (corrosion under insulation, CUI).
  • a method of separately adding HCl, which is used as a catalyst, to hexamethyldisiloxane is also used. This method is used to modify the surface and simultaneously produce hexamethyl Disiloxane fills the pores to convert the hydrogel into an organic gel, but similarly, some of the added chlorine remains in the silica airgel blanket that is ultimately obtained.
  • the silica airgel blanket manufacturing method of the present invention does not use a compound containing chlorine (Cl) during the manufacturing process, so the final hydrophobic silica airgel blanket produced does not contain residual chlorine.
  • the method for producing a silica airgel blanket of the present invention includes the steps of 1) preparing silica sol containing a water glass solution; 2) impregnating the blanket substrate with the silica sol; 3) preparing a wet gel by gelling the silica sol while impregnating the blanket substrate with the silica sol; 4) immersing the wet gel in an aqueous acid mixture solution containing aqueous acetic acid and nitric acid and surface modifying the wet gel with an alkyldisiloxane-based compound; and 5) drying the surface-modified wet gel, wherein the acetic acid concentration (w/w) after step 4) is 30% to 90%, and the nitric acid concentration (w/w) is 5 to 10. It is characterized by %.
  • the method for producing a silica airgel blanket of the present invention promotes acetic acid, an amphiphilic substance that can dissolve both water and alkyldisiloxane-based compounds used as surface modifiers, and protonation of alkyldisiloxane-based compounds.
  • the amount of acetic acid and nitric acid used should be such that the concentration of acetic acid and nitric acid after the surface modification in step 4) [weight (w) / weight (w)] can satisfy a certain value.
  • the silica sol of step 1) can be prepared by mixing a water glass solution and an acid catalyst as a silica precursor.
  • the acid catalyst in the silica sol may be included in a molar ratio of 1 to 3 relative to the water glass in the water glass solution.
  • the water glass solution may be a diluted solution obtained by adding and mixing distilled water to water glass, and the water glass may be sodium silicate (Na 2 SiO 3 ), which is an alkali silicate salt obtained by melting silicon dioxide (SiO 2 ) and an alkali. there is.
  • the water glass dispersion may contain 1% to 13% by weight of silicon dioxide (SiO 2 ). If the water glass dispersion contains silicon dioxide in a content lower than the above range, the airgel may not be properly formed, and if the silicon dioxide is contained in a content higher than the above range, gelation does not proceed easily or does not proceed easily. Surface area may be reduced.
  • silicon dioxide SiO 2
  • any one or more of organic acids and inorganic acids that do not contain chlorine in the compound molecular structure can be used to exclude chlorine from the final manufactured silica airgel blanket, and include, for example, acetic acid, oxalic acid, nitric acid, sulfuric acid, and hydrofluoric acid. It may be one or more types selected from the group, and specifically, considering the aqueous acid mixture solution used in the surface modification in step 4), nitric acid, acetic acid, or a mixture thereof may be used.
  • the acid catalyst may be included in an amount such that the pH of the silica sol is 3 to 10. If the pH of the silica sol is outside the above range, gelation in step 3) may not be easy, or the gelation rate may be too fast or too slow, which may reduce processability.
  • Step 2) is a step of impregnating the blanket substrate with the silica sol.
  • the blanket substrate according to an embodiment of the present invention may be specifically a porous substrate in terms of improving the thermal insulation of the silica airgel blanket.
  • a porous blanket substrate When a porous blanket substrate is used, the silica sol easily penetrates into the substrate and forms airgel uniformly inside the blanket substrate, allowing the manufactured silica airgel blanket to have excellent thermal insulation properties.
  • the blanket substrate that can be used according to an embodiment of the present invention may be a film, sheet, net, fiber, foam, non-woven fabric, or a laminate of two or more layers thereof. Additionally, depending on the use, surface roughness may be formed or patterned on the surface. More specifically, the blanket substrate may be a fiber that can further improve thermal insulation performance by including a space or void that facilitates insertion of silica airgel into the blanket substrate. Additionally, it may be desirable for the blanket substrate to have low thermal conductivity.
  • the blanket substrate is polyamide, polybenzimidazole, polyaramid, acrylic resin, phenolic resin, polyester, polyether ether ketone (PEEK), polyolefin (e.g., polyethylene, polypropylene, or copolymers thereof). etc.), cellulose, carbon, cotton, wool, hemp, non-woven fabric, glass fiber, or ceramic wool. More specifically, in the present invention, the blanket substrate may be glass fiber.
  • impregnation may be performed by pouring silica sol into a reaction vessel containing a blanket substrate or by wetting the blanket substrate with silica sol.
  • the blanket substrate can be lightly pressed to ensure sufficient impregnation.
  • the blanket substrate can be pressed to a certain thickness with a certain pressure to remove excess silica sol, thereby reducing the drying time.
  • Step 3) is a step for producing a hydrophobic silica wet gel blanket.
  • the wet gel blanket can be produced by allowing the silica sol impregnated in the blanket substrate to undergo gelation.
  • the gelation may represent a sol-gel reaction
  • the “sol-gel reaction” may be the formation of a network structure from a silicon unit precursor material.
  • the network structure is a flat network-shaped structure in which certain polygons of one or more types of atomic arrangements are connected, or a three-dimensional skeletal structure by sharing vertices, edges, faces, etc. of a specific polyhedron. It may represent the structure forming the .
  • the manufacturing method according to an embodiment of the present invention may further include aging the silica wet gel blanket prepared after gelation in step 3).
  • the maturation is not particularly limited, but may be performed, for example, by leaving it at room temperature (25°C) to 90°C for 1 hour to 24 hours.
  • the manufacturing method according to an embodiment of the present invention can form the network structure of the wet gel in the silica wet gel blanket more firmly by subjecting the silica wet gel blanket to the above-described aging process, and thus have excellent pore characteristics. there is.
  • step 4 the wet gel is immersed in an aqueous acid mixture containing acetic acid and nitric acid aqueous solution and the surface is modified with an alkyldisiloxane-based compound to form a hydrophobic silica wet gel blanket.
  • the process of adding the aqueous acid mixture solution to the wet gel to immerse the wet gel in the aqueous acid mixture solution and then adding the alkyldisiloxane-based compound to the wet gel may be performed, and in another example of the present invention, the acid mixture aqueous solution and the alkyldisiloxane-based compound may be simultaneously added to the wet gel.
  • the acid mixture aqueous solution containing water having a higher density than the alkyldisiloxane-based compound is positioned downward.
  • the layers are separated into an alkyldisiloxane-based compound layer in the upper layer and an acid mixture aqueous solution layer in the lower layer.
  • the acid mixture aqueous solution In the process of immersing the wet gel in the acid mixture aqueous solution, the acid mixture aqueous solution enters the wet gel by diffusion, and the moisture present in the wet gel comes out of the wet gel and moves to the acid mixture aqueous solution layer. In this way, when immersion with the acid mixture aqueous solution is completed, the acid concentration inside the wet gel and the acid concentration of the acid mixture aqueous solution outside the wet gel may be in equilibrium.
  • Acetic acid which is an amphiphilic substance contained in the acid mixture aqueous solution, allows a trace amount of the alkyldisiloxane-based compound to be dissolved into the acid mixture aqueous solution at the interface between the alkyldisiloxane-based compound layer and the acid mixture aqueous solution layer, thereby dissolving the alkyldisiloxane-based compound into the acid mixture aqueous solution.
  • the surface of the wet gel is modified by the disiloxane-based compound.
  • the aqueous solution filling the wet gel is replaced with the alkyldisiloxane-based compound, and the wet gel is filled with the alkyldisiloxane-based compound, and the aqueous solution flows out of the wet gel. comes out and moves to the acid mixture aqueous solution layer.
  • the acid concentration inside the wet gel and the acid concentration outside the wet gel reach equilibrium.
  • the wet gel contains moisture, it is initially located in the acid mixture aqueous solution layer, and as surface modification occurs and the wet gel is filled with the alkyldisiloxane-based compound, it gradually rises and moves to the alkyldisiloxane-based compound layer. do.
  • hexamethyldisiloxane for example, is used as the alkyldisiloxane-based compound in step 4
  • a reaction as shown in Scheme 2 below may be performed.
  • the acetic acid concentration (w/w) after step 4) refers to the concentration of acetic acid contained in the acid mixture aqueous solution layer after step 4), and can be expressed by equation 1 below.
  • the concentration of acetic acid can be calculated by measuring the weight of water in the acid mixture aqueous solution layer after step 4) and measuring the weight of acetic acid in the acid mixture aqueous solution layer using gas chromatography (GC).
  • GC gas chromatography
  • the weight of water in the acid mixture aqueous solution layer can be measured using a Karl Fischer moisture meter (Si Analytics Titro Line 7000).
  • Acetic acid concentration weight of acetic acid in the acid mixture aqueous solution layer / (weight of acetic acid in the acid mixture aqueous solution layer + total weight of water in the acid mixture aqueous solution layer) ⁇ 100
  • the concentration (w/w) of nitric acid after step 4) refers to the concentration of nitric acid contained in the acid mixture aqueous solution layer after step 4), and can be expressed by Equation 2 below.
  • the concentration of nitric acid can be calculated by measuring the weight of water in the acid mixture aqueous solution layer after step 4) and using the weight of nitric acid in the acid mixture aqueous solution layer, where the amount of nitric acid after step 4) is It is the same as the amount of nitric acid added when preparing the acid mixture aqueous solution.
  • Nitric acid concentration (w/w) Input weight of nitric acid / (Introduced weight of nitric acid + Total weight of water in the acid mixture aqueous solution layer) ⁇ 100
  • the acid concentration inside the wet gel and the acid concentration outside the wet gel are in equilibrium, so the acid concentration of the acid mixture aqueous solution layer after immersion can be measured.
  • the acid concentration inside the wet gel can be known, and thus the acid concentration involved in surface modification can be determined.
  • the water contained in the acid mixture aqueous solution layer is the water contained in the acetic acid aqueous solution and the nitric acid aqueous solution, the water contained in the wet gel, and the water derived from the hydrophilic hydrophobization reaction of the wet gel.
  • the water may remain after step 4), and their total weight may be the total weight of water in the acid mixture aqueous solution layer.
  • Step 4) can be performed by sequentially immersing the wet gel in an aqueous acid mixture solution and then sequentially modifying the surface with the alkyldisiloxane-based compound.
  • the acetic acid concentration (w/w) may be 30% to 90%, specifically 35% to 80%, 36% to 80%, and more specifically 36% to 78%.
  • the acetic acid when acetic acid is used in an amount such that the acetic acid concentration is 30% to 90%, the acetic acid enables effective contact between the hydrophilic wet gel and the hydrophobic alkyldisiloxane-based compound, resulting in a smooth surface modification reaction. You can make this happen. If the acetic acid concentration (w/w) is too low, the reaction between the hydrophilic wet gel and the hydrophobic alkyldisiloxane-based compound may not occur, so the surface modification reaction may not proceed smoothly. Additionally, if the acetic acid concentration is excessive, more acetic acid than necessary must be added, which may reduce economic efficiency.
  • the nitric acid concentration (w/w) is 5% to 10%, specifically 5% to 9%, 5% to 8%, 5.5% to 8%, 5.5% to 7.5%, and more. Specifically, it may be 5.5% to 7.3%.
  • the nitric acid concentration satisfies the above range, protonation of the alkyldisiloxane-based compound is effectively promoted, resulting in an excellent surface modification reaction rate.
  • the nitric acid concentration is too low, the surface modification reaction rate decreases, and the surface modification reaction by the alkyldisiloxane-based compound is not sufficiently achieved, so that the degree of hydrophobization of the wet gel decreases and thus the heat conduction of the final manufactured silica airgel blanket degree may increase.
  • the nitric acid concentration is excessive, the oxidizing power of nitric acid increases and dangerous side reactants may be formed through reaction with acetic acid, thereby reducing stability.
  • the method for manufacturing a silica airgel blanket according to an embodiment of the present invention includes, when immersing the wet gel in the acid mixture aqueous solution in step 4), the acid mixture aqueous solution satisfies the weight ratio of acetic acid and nitric acid, After step 4), by checking whether the acetic acid concentration and nitric acid concentration satisfy the above-mentioned values, surface modification can be achieved quickly, sufficiently and effectively for the wet gel, especially the hydrogel prepared using the water glass solution.
  • the alkyldisiloxane-based compound may be added in a volume ratio of 1 to 3 times, specifically 1 to 2.5 times, and more specifically 1 to 2 times the volume of the wet gel.
  • the alkyldisiloxane-based compound needs to be added in a volume of at least 1 time based on the volume of the wet gel to modify the wet gel and replace the solvent of the wet gel, and the amount of the alkyldisiloxane-based compound added is Since the size of the equipment needs to be increased when increasing, the alkyldisiloxane-based compound can be added within the above range based on the volume of the wet gel.
  • the alkyldisiloxane-based compound may be a hexaalkyldisiloxane-based compound, specifically hexa(C 1-8 alkyl)disiloxane, and more specifically hexamethyldisiloxane.
  • the surface modification reaction may be performed at a temperature of 25°C to 95°C. Additionally, a stirring process may be performed in the process of immersing the wet gel in an aqueous acid mixture solution and the process of surface modifying the wet gel with an alkoxydisiloxane-based compound.
  • the stirring is not particularly limited, but may be stirred at a speed of, for example, 50 rpm to 700 rpm.
  • step 4) may be performed for 2 to 24 hours, and is preferably performed for 4 to 22 hours in terms of improving the economics of the process while maintaining the surface modification effect at an excellent level, or It can be carried out for 8 to 20 hours.
  • step 4) involves immersing the wet gel in an aqueous acid mixture solution, and then sequentially performing surface modification with the alkyldisiloxane-based compound.
  • the process of immersing in the acid mixture aqueous solution may be performed for 30 minutes to 4 hours, specifically 30 minutes to 3 hours, more specifically 1 hour to 3 hours, and surface modification with the alkyldisiloxane-based compound.
  • the process may be carried out for 1 hour and 30 minutes to 20 hours, specifically 3 hours to 19 hours, and more specifically 6 hours to 18 hours.
  • Step 5) is a step of manufacturing a hydrophobic silica airgel blanket by drying the hydrophobic silica wet gel blanket.
  • the step of washing before drying may be further performed.
  • the washing is to remove impurities (sodium ions, unreacted products, by-products, etc.) generated during the reaction to obtain a high-purity hydrophobic silica airgel blanket.
  • the hydrophobic silica wet gel is added with a non-polar organic solvent, and washed for 20 minutes. It can be performed by stirring for 1 hour, but is not limited to this.
  • the drying may be performed through methods such as normal pressure drying and supercritical drying, but is not limited thereto.
  • atmospheric drying may be a method of drying at atmospheric pressure for 1 to 12 hours under temperature conditions of 100°C to 190°C
  • supercritical drying may be a method performed using CO 2 in a supercritical state.
  • it has the advantage of being relatively simple and economical, and in the case of supercritical drying, it may have the advantage of effectively removing the fluid inside the gel.
  • the method for manufacturing the hydrophobic silica airgel blanket according to an embodiment of the present invention can greatly improve the surface modification efficiency, and thus has physical properties such as excellent pore characteristics and high hydrophobicity, thereby improving the thermal insulation performance to an excellent level. It can be secured.
  • hydrophobization of the airgel is carried out under chlorine-free (Cl-free) conditions, so chlorine is not contained in the final silica airgel blanket produced or chlorine is included. Since is minimized, the possibility of causing corrosion of the area where the silica airgel blanket is applied due to chlorine can be excluded.
  • the silica airgel blanket according to an embodiment of the present invention has a thermal conductivity of 12 mW/mK to 19 mW/mK and a Cl content of 0 ppm to 500 ppm.
  • the thermal conductivity of the silica airgel blanket according to an embodiment of the present invention is specifically 12 mW/mK or more, 13 mW/mK or more, 14 mW/mK or more, 15 mW/mK or more, or 16 mW/mK or more to 19 mW/ It may be mK or less, 18.5 mW/mK or less, or 18.3 mW/mK or less.
  • the silica airgel blanket according to an embodiment of the present invention does not contain Cl derived from the airgel, but may contain a small amount of Cl derived from the blanket substrate of the silica airgel.
  • the Cl content of the silica airgel blanket according to an embodiment of the present invention may specifically be 0 ppm to 500 ppm, ppm to 400 ppm, 0 ppm to 300 ppm, or 0 ppm to 200 ppm.
  • the silica airgel blanket manufactured according to the manufacturing method according to an embodiment of the present invention can be used for a variety of purposes, including thermal insulation applications, including applications requiring insulation, for example, at a temperature of 650°C or lower.
  • thermal insulation applications including applications requiring insulation, for example, at a temperature of 650°C or lower.
  • it can be used as an insulation material for pipes such as double-casing pipes, insulation of aircraft and its parts, insulation of buildings, insulation of spacecraft, insulation of automobiles, insulation of clothing, insulation of shoes, etc.
  • the airgel blanket can be used in the same way as when an airgel mat or a plurality of airgels are used.
  • the acid mixture aqueous solution prepared by mixing 140 g of acetic acid ( ⁇ 97%) and 15 g of nitric acid 70% (w/w) aqueous solution was poured onto the glass fiber impregnated with the wet gel and maintained in an oven at 60°C for 2 hours. After immersion, hexamethyldisiloxane (HMDSO, 160 g) was added and the temperature was maintained in an oven at 75°C for 16 hours to proceed with the surface modification reaction.
  • HMDSO hexamethyldisiloxane
  • the prepared hydrophobic silica wet gel blanket was recovered and completely dried in a forced circulation dryer at 150°C for 4 hours to prepare a hydrophobic silica airgel blanket.
  • Example 1 When preparing the acid mixture aqueous solution in Example 1, the content of acetic acid ( ⁇ 97%) was changed to 185 g, and instead of the 70% (w/w) nitric acid aqueous solution, 70% (w/w) nitric acid was added to 95 g of water.
  • a hydrophobic silica airgel blanket was prepared in the same manner as Example 1, except that a dilute aqueous nitric acid solution prepared by mixing 20 g of an aqueous solution was used.
  • Example 2 When preparing the aqueous acid mixture solution in Example 1, the content of acetic acid ( ⁇ 97%) was changed to 280 g, and instead of the 70% (w/w) nitric acid aqueous solution, 70% (w/w) nitric acid was added to 142 g of water.
  • a hydrophobic silica airgel blanket was prepared in the same manner as Example 1, except that a dilute aqueous nitric acid solution prepared by mixing 30 g of an aqueous solution was used.
  • a hydrophobic silica airgel blanket was prepared in the same manner as in Example 1, except that the content of acetic acid ( ⁇ 97%) was changed to 80 g when preparing the acid mixture aqueous solution in Example 1.
  • a hydrophobic silica airgel blanket was prepared in the same manner as in Example 1, except that the content of acetic acid ( ⁇ 97%) was changed to 500 g when preparing the acid mixture aqueous solution in Example 1.
  • a hydrophobic silica airgel blanket was prepared in the same manner as Example 1, except that only 140 g of 35 wt% hydrochloric acid was used instead of the acid mixture aqueous solution of acetic acid and nitric acid.
  • a hydrophobic silica airgel blanket was prepared in the same manner as Example 1, except that only 140 g of acetic acid ( ⁇ 97%) was used instead of the acid mixture aqueous solution of acetic acid and nitric acid.
  • a hydrophobic silica airgel blanket was prepared in the same manner as in Example 1, except that only 140 g of a 70% (w/w) aqueous solution of nitric acid was used instead of the acid mixture aqueous solution of acetic acid and aqueous nitric acid in Example 1. Manufactured.
  • Example 1 When preparing the acid mixture aqueous solution in Example 1, instead of the 70% (w/w) nitric acid aqueous solution, a dilute aqueous nitric acid solution prepared by mixing 71.3 g of water with 15 g of 70% (w/w) nitric acid aqueous solution was mixed with acetic acid ( ⁇ A hydrophobic silica airgel blanket was prepared in the same manner as Example 1, except that it was used with 140 g (97%).
  • Example 1 When preparing the aqueous acid mixture solution in Example 1, instead of the 70% (w/w) aqueous nitric acid solution, a dilute aqueous nitric acid solution prepared by mixing 20 g of 70% (w/w) nitric acid solution with 100 g of water was mixed with acetic acid ( ⁇ A hydrophobic silica airgel blanket was prepared in the same manner as Example 1, except that it was used with 70 g (97%).
  • a hydrophobic silica airgel blanket was prepared in the same manner as Example 1, except that the amount of nitric acid 70% (w/w) aqueous solution used in preparing the acid mixture aqueous solution was changed to 30 g.
  • the amount of acetic acid in the acid mixture aqueous solution after acid immersion was obtained using gas chromatography (GC) analysis.
  • Acetic acid concentration after acid immersion weight of acetic acid / (weight of acetic acid + weight of water ⁇ 100
  • the nitric acid concentration was calculated by taking the weight of the initially introduced nitric acid as the weight of nitric acid in the acid mixture aqueous solution.
  • Nitric acid concentration after acid immersion weight of nitric acid added / (weight of nitric acid added + weight of water)
  • silica airgel blankets prepared in Examples 1 to 5 and Comparative Examples 1 to 6 were analyzed using a combustion ion chromatography (combusion IC) system (AQF-2100H, ICS-3000, Thermo Fisher Scientific). The amount of Cl was measured.
  • combustion IC combustion ion chromatography
  • Examples 1 to 5 used an acid mixture aqueous solution containing acetic acid and nitric acid aqueous solution as the acid mixture aqueous solution, and after acid immersion, the acetic acid concentration (w/w) of the acid mixture aqueous solution layer was 30% to 90%, and the nitric acid concentration It was confirmed that a silica airgel blanket with low thermal conductivity was manufactured by manufacturing a silica airgel blanket with a manufacturing method that satisfies (w/w) 5 to 10%.
  • Comparative Example 2 is an example in which only acetic acid was used without using nitric acid, and it was confirmed that thermal conductivity increased due to a slow surface modification rate and a decrease in physical properties occurred.
  • Comparative Example 3 is an example in which only nitric acid was used without acetic acid, and since acetic acid, an amphiphilic solvent, was not used, the reaction between hexamethyldisiloxane and the wet gel did not occur, so no surface modification occurred, and thus high thermal conductivity was exhibited. It was.
  • Comparative Example 4 is an example in which the nitric acid concentration of the acid mixture aqueous solution layer is less than 5% after acid immersion
  • Comparative Example 5 is an example in which the acetic acid concentration of the acid mixture aqueous solution layer is less than 30% after acid immersion, respectively. It was confirmed that the thermal conductivity of the silica airgel blanket manufactured as nitric acid and acetic acid were used in an insufficient amount compared to the appropriate amount showed a high value, and a decrease in physical properties occurred.
  • Comparative Example 6 acetic acid and nitric acid were used together, but after acid immersion, the nitric acid concentration in the acid mixture aqueous solution layer was 10% or more. The amount of nitric acid used exceeded the appropriate amount, and a side reaction between acetic acid and nitric acid occurred, causing wetting. No reaction to surface modify the gel occurred.

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  • Chemical & Material Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Silicon Compounds (AREA)

Abstract

La présente invention concerne un procédé de fabrication d'un matelas d'aérogel de silice hautement hydrophobe ayant une excellente efficacité de modification de surface et ne contenant pas de chlore résiduel et un matelas d'aérogel de silice ne contenant pas de chlore résiduel fabriqué par ce procédé.
PCT/KR2023/010608 2022-07-22 2023-07-21 Procédé de fabrication d'un matelas d'aérogel de silice hydrophobe et matelas d'aérogel de silice WO2024019593A1 (fr)

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KR20170062261A (ko) * 2015-11-27 2017-06-07 주식회사 엘지화학 소수성의 실리카 에어로겔의 제조방법 및 이로부터 제조된 소수성의 실리카 에어로겔
KR20170104914A (ko) * 2016-03-08 2017-09-18 주식회사 엘지화학 에어로겔 블랑켓의 제조방법 및 이로부터 제조된 에어로겔 블랑켓
KR20170112985A (ko) * 2016-03-28 2017-10-12 주식회사 엘지화학 저분진 고단열 에어로겔 블랭킷의 제조방법
CN108658576A (zh) * 2018-06-28 2018-10-16 盱眙博图凹土股份有限公司 一种复合二氧化硅气凝胶毡的制备方法

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KR20170062261A (ko) * 2015-11-27 2017-06-07 주식회사 엘지화학 소수성의 실리카 에어로겔의 제조방법 및 이로부터 제조된 소수성의 실리카 에어로겔
KR101654795B1 (ko) * 2016-02-05 2016-09-06 김현철 고단열 에어로겔 함침 매트의 제조 방법
KR20170104914A (ko) * 2016-03-08 2017-09-18 주식회사 엘지화학 에어로겔 블랑켓의 제조방법 및 이로부터 제조된 에어로겔 블랑켓
KR20170112985A (ko) * 2016-03-28 2017-10-12 주식회사 엘지화학 저분진 고단열 에어로겔 블랭킷의 제조방법
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